From Joomla! Documentation
- Title: Module must have a title
The Similar Tags Module displays links to other items with similar tags. The closeness of the match can be specified.
- Maximum items: (1/2/3/4/5/6/7/...). Maximum number of items to display
- Match type: (All/Any/Half). How closely an item's tags need to match. All - requires that all tags in the displayed item be matched. Any - requires that at least one tag match. Half - requires that at least half of the tags match (rounded up in the case of decimals).